Devices for weighing small objects

ABSTRACT

Device for rapidly determining the weight of light weight objects comprising a tubular member having a vertical duct therethrough for the passage of air. The duct is open at the top of the member and connected to means for supplying air for passage through the duct and out through the top of said member. Connected to the top of the member is a platform restricted in its lateral movement and adapted to be moved vertically to a predetermined point above said member to allow air from the duct in said member to exit beneath the platform, which platform is thereby suspended by the pressure of the exiting air. A calibrated pressure gauge is associated with the air supply means which registers the difference in pressure in the air supply means when an object to be weighed is placed on the platform and depresses the platform. The weighing device is particularly suited for rapid quality control procedures in the manufacture of light weight objects, such as cigarettes.

United States Patent Hester [72] Inventor: Benny Lee Hester,Winston-Salem, NC.

[73) Assignee: R. J. Reynolds Tobacco Company, Winston-Salem, NC.

[22] Filed: June 24, 1971 [21] Appl. No.: 156,177

[52] U.S.Cl..... .177/20l,177/1, 177/207 [51) Int. Cl. ..Gtllg 5/04 [58]Field of Search 177/1, 201, 207-209, 177/212 [56] References CitedUNITED STATES PATENTS 751,295 2/1904 Jones ...177/20l X 751,296 2/1904.lones...... ...l77/201 X 2,773,685 12/1956 Aagaard ..l77/212 X June 27,1972 Primary Examiner-Robert S. Ward, Jr. Attorney-Stepno & Neilan [5 7]ABSTRACT Device for rapidly determining the weight of light weightobjects comprising a tubular member having a vertical duct therethroughfor the passage of air. The duct is open at the top of the member andconnected to means for supplying air for passage through the duct andout through the top of said member. Connected to the top of the memberis a platform restricted in its lateral movement and adapted to be movedvertically to a predetermined point above said member to allow air fromthe duct in said member to exit beneath the platform, which platform isthereby suspended by the pressure of the exiting air. A calibratedpressure gauge is associated with the air supply means which registersthe difference in pressure in the air supply means when an object to beweighed is placed on the platform and depresses the platform. Theweighing device is particularly suited for rapid quality controlprocedures in the manufacture of light weight objects, such ascigarettes.

5 Claims, 1 Drawing Flgure PATENTEUJuum I972 llllln'll'lll'ulll I llINVENTOR. BENNY LEE HESTER DEVICES FOR WEIGHING SMALL OBJECTS BACKGROUNDOF THE INVENTION This invention relates to weighing devices. Moreparticularly, this invention relates to devices especially adapted forrapidly weighing small, light objects.

The quality control of consumer products is a recognized necessity innearly all manufacturing operations which produce such products. As aconsequence, many manufacturers have installed quality controlprocedures which are carried out in association with their manufacturingprocesses. In many manufacturing processes, these quality controlprocedures are very rigid both for the protection of the consumer andthe benefit of the manufacturer.

In manufacturing processes wherein small objects are the product, suchas cigarettes, pharmaceutical dosage tablets, small metallic or plasticobjects, and the like, at least one of the steps necessary for thequality control of the objects being produced is a determination of theweight of the individual objects. This is a very tedious and timeconsuming operation. Due to the fact that the objects produced weigh solittle, e. g., a cigarette weighs about 1 gram or less, it is extremelydifl'icult to obtain accurate weight measurements in a short period oftime. As a result, either the quality control operator expends a largeamount of time in accurately determining the weight of the objects beingproduced for providing rigid quality control, or the objects are weighedin a short period of time, but inaccurately, which reduces the qualitycontrol standards of the operation.

Methods have been devised in an attempt to overcome the above mentioneddifficulties in obtaining a rigid quality con trol in the manufacture ofsmall objects. However, these methods have not proved entirelysatisfactory due to either the time consumption required or the degreeof error in the weight measurement.

SUMMARY OF THE INVENTION Accordingly, it is an object of this inventionto provide a device for accurately determining the weight of small,light weight objects.

It is a further object of this invention to provide a device whichaccurately determines the weight of small objects in a very short periodof time.

It is a still further object of this invention to provide a weighingdevice which is simple in operation and efficient in results and whichis especially suited for the weighing of small objects.

Briefly, in accordance with this invention, there is provided a weighingdevice which is composed of a tubular member having a vertical ductextending therethrough which allows for the passage of air through themember. The duct is open at the top of said member and is connected tomeans for supplying air for passage through the duct out through the topof said member. A platform is connected to the top of the member and isadapted to be suspended above the top of said member by the pressure ofair passing through said duct and out through the top of said member.Preferably, the platform is connected to the member by pins whichrestrain its lateral movement and also its vertical movement to apredetennined point a slight distance above the member. There is furtherprovided means, e.g., a calibrated pressure gauge, connected to the airsupply means for determining the difference in the pressure within theair supply means when an object to be weighed is placed on the platformcausing it to fall which results in a back pressure build up in the airsupply line.

BRIEF DESCRIPTION OF THE DRAWING In the drawing: The FIGURE is aperspective view partly in section of the weighing device of thisinvention.

DETAILED DESCRIPTION OF THE INVENTION The invention will be more fullyunderstood with reference to the accompanying drawings wherein likenumerals indicate like parts.

In the drawing, a tubular member 1, supported by a base 2, has locatedtherein a vertical duct 3 for the passage of air therethrough. Air, froma source not shown, passes through a supply line 4 into the verticalduct 3 and out through the top of the member 1. The passage of airthrough the duct 3 causes a platform 5 to rise in order to permit theexit of the air to the atmosphere. The platform 5 is connected to thetop of member 1 by restraining pins 6 which restrict platform 5 in itslateral movement. Preferably restraining pins 6 terminate in pin heads60 which serve to prevent platform 5 from being disconnected from member1 in the event that the pressure through duct 3 becomes excessive. Thedistance from the top of member I to the pin heads 60 may vary dependingupon the type and variety of objects to be weighed. Restraining pins 6pass through openings in platform 5, and while the pin heads 60 arelarger than the openings in the platform, the pins themselves should beof a substantially smaller diameter than the openings in platfonn 5 soas to permit free, frictionless vertical movement of platform 5 on therestraining pins.

The air supply line 4 is preferably provided with a pressure regulator 8for the regulation of the pressure through the line into duct 3. Apressure gauge 7 is also provided in association with line 4 fordetermining the pressure of the air passing therethrough. It should beunderstood that while a pressure gauge is illustrated in the drawing,any other suitable means may be used to detect the difference inpressure in line 4. When a gauge is used, it is preferably calibrated toprovide a reading in the desired units. For example, when the device isused to weigh a cigarette, the gauge could be calibrated to provide asignal when the weight of the object varied, for example, plus or minus5 percent, from 1 gram.

It will be appreciated that since the device of this invention is to beused for weighing small objects of the character described above, theentire device operates under very low flow rate conditions. That is, theflow rate of the air passing through the supply line 4 into the duct 3is extremely low in comparison to other devices which operate with theuse of pressurized fluids, such as air. As a consequence, the supplyline 4 is preferably provided with a flow rate metering orifice 9.

While there are shown two restraining pins 6, it should be understoodthat the number of restraining pins required will be dependent upon theshape of the platform and the shape of the tubular member. The criticalfactors in relation to the restraining pins are, as mentioned above,that the platform be allowed to freely float between the top of themember I and the pin heads 60, and also, that the platform remainsubstantially horizontal during use. Again, while the shape of tubularmember 1 is illustrated as being cylindrical, this is not a criticalfeature of this invention, and any desired shape may be used.

In operation of the device of this invention, air, from a source notshown, is passed into air supply line 4 and through pressure regulator 8which is adjusted to provide the desired air pressure. The air passesfrom regulator 8 through line 4, past orifice 9 and gauge 7 into duct 3and out of the top of member 1. This causes the platform 5 to rise andin effect ride on the film of the air escaping from the duct 3. Whenproperly positioned, the air will escape from duct 3 into the atmospherearound the entire perimeter of platform 5. The air pressure required tohold the platfonn in its desired position is recorded on the pressuregauge 7. The object to be weighed, e.g., a cigarette, is placed on theplatform 5 which causes the same to fall thereby reducing the clearanceor exit area for the air exiting from duct 3. This in turn causes thepressure in duct 3 and line 4 to increase to an amount sufiicient tosupport the platform with the object. The back pressure build up in line4 is immediately recorded on the pressure gauge 7 and the weight of theobject thereby determined. Conveniently, pressure gauge 7 may beadditionally connected to signal means 10 which indicates to theoperator that the object being weighed is beyond the acceptabledeviation from the nonnal or desired weight thereof.

Thus, the weighing device of the instant invention provides an efficientmethod for weighing small, light weight objects and is simple tooperate. A further advantage of the device described above is the factthat the device has an extremely fast response time; that is the weightof the object being placed on the platform is generally determined in aperiod of time between and milliseconds, never more than 0.5 second.Furthermore, due to the nature of the operation of the device described,there is very little, if any, possibility of overshoot; that is, theweight indicated on the pressure gauge or other like device will veryrarely, if ever, exceed the exact weight of the object placed on thefloating platform.

As many apparently widely different embodiments of this invention may bemade without departing from the spirit and scope thereof. it is to beunderstood that same is not to be limited to the specific embodimentsthereof except as claimed in the appended claims.

What is claimed is:

l. A weighing device comprising a tubular member having a vertical ducttherein adapted for the passage of air, said duct being opened at thetop of said member, air supply means connected to said duct, a platformconnected to the top of said member and adapted to be suspended abovethe top of said member by air passing through said duct, and meansconnected to said air supply means for determining the difference inpressure therein when an object to be weighed is placed on saidplatform.

2. The weighing device as described in claim 1, wherein the means fordetermining the pressure difference is a pressure gauge.

3. A weighing device as described in claim 2, wherein the pressure gaugeis calibrated to determine the weight of an object placed on saidplatform.

4. A weighing device as described in claim 1, wherein said platform isconnected to the top of said member by restraining pins.

5. A weighing device as described in claim 4, wherein said platform isadapted to allow air exiting from said vertical duct to escape into theatmosphere around the entire perimeter of said platform.

i a t r r

1. A weighing device comprising a tubular member having a vertical ducttherein adapted for the passage of air, said duct being opened at thetop of said member, air supply means connected to said duct, a platformconnected to the top of said member and adapted to be suspended abovethe top of said member by air passing through said duct, and meansconnected to said air supply means for determining the difference inpressure therein when an object to be weighed is placed on saidplatform.
 2. The weighing device as described in claim 1, wherein themeans for determining the pressure difference is a pressure gauge.
 3. Aweighing device as described in claim 2, wherein the pressure gauge iscalibrated to determine the weight of an object placed on said platform.4. A weighing device as described in claim 1, wherein said platform isconnected to the top of said member by restraining pins.
 5. A weighingdevice as described in claim 4, wherein said platform is adapted toallow air exiting from said vertical duct to escape into the atmospherearound the entire perimeter of said platform.